[PATCH V2] tools/perf/builtin-lock: Fix return code for functions in __cmd_contention

[Athira Rajeev]

perf lock contention returns zero exit value even if the lock contention
BPF setup failed.

  # ./perf lock con -b true
  libbpf: kernel BTF is missing at '/sys/kernel/btf/vmlinux', was CONFIG_DEBUG_INFO_BTF enabled?
  libbpf: failed to find '.BTF' ELF section in /lib/modules/6.13.0-rc3+/build/vmlinux
  libbpf: failed to find valid kernel BTF
  libbpf: kernel BTF is missing at '/sys/kernel/btf/vmlinux', was CONFIG_DEBUG_INFO_BTF enabled?
  libbpf: failed to find '.BTF' ELF section in /lib/modules/6.13.0-rc3+/build/vmlinux
  libbpf: failed to find valid kernel BTF
  libbpf: Error loading vmlinux BTF: -ESRCH
  libbpf: failed to load object 'lock_contention_bpf'
  libbpf: failed to load BPF skeleton 'lock_contention_bpf': -ESRCH
  Failed to load lock-contention BPF skeleton
  lock contention BPF setup failed
  # echo $?
   0

Fix this by saving the return code for lock_contention_prepare
so that command exits with proper return code. Similarly set the
return code properly for two other functions in builtin-lock, namely
setup_output_field() and select_key().

Signed-off-by: Athira Rajeev <atrajeev at linux.vnet.ibm.com>
---
Changelog:
 v1 -> v2
 Fixed return code in functions: setup_output_field()
 and select_key() as pointed out by Namhyung.

 tools/perf/builtin-lock.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 208c482daa56..94a2bc15a2fa 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -2049,7 +2049,8 @@ static int __cmd_contention(int argc, const char **argv)
 				goto out_delete;
 		}
 
-		if (lock_contention_prepare(&con) < 0) {
+		err = lock_contention_prepare(&con);
+		if (err < 0) {
 			pr_err("lock contention BPF setup failed\n");
 			goto out_delete;
 		}
@@ -2070,10 +2071,14 @@ static int __cmd_contention(int argc, const char **argv)
 		}
 	}
 
-	if (setup_output_field(true, output_fields))
+	err = setup_output_field(true, output_fields);
+	if (err) {
+		pr_err("Failed to setup output field\n");
 		goto out_delete;
+	}
 
-	if (select_key(true))
+	err = select_key(true);
+	if (err)
 		goto out_delete;
 
 	if (symbol_conf.field_sep) {
-- 
2.43.5